Stirrer



April 7, 1964 w. w. CASTOR 3,128,084

I STIRRE'R Filed Nov. 15, 1961 INVENTOR WILBUR W, CASTOR.

ATTORN EYS United States Patent 3,128,084 STIRRER Wilbur W. Castor, 746 Shady Lane, Pittsburgh 34, Pa. Filed Nov. 15, 1961, Ser. No. 152,424 9 Claims. (Q1. 259-134) This invention relates to a stirrer, and more particularly to a stirrer having a disc provided with a plurality of apertures therethrough oriented with respect to one another to impart maximum turbulence and, accordingly, maximum efiiciency mixing of liquids and semi-liquids.

Stirrers and agitators for mixing fluids are known in the art to contain discs with apertures arranged with axes along random directions. It has been found that indiscriminate orientation of the axes of apertures through stirrer plates does not produce the desired turbulence of liquids to be mixed intimately. Attempts have been made to cause greater turbulence by increasing the speed of rotation of the stirrer disc and by extending the mixing time. However, the specific speed of the stirrer to produce maximum efficiency of mixing reaches an upper limit, beyond which the turbulence is actually decreased. Therefore, only by prolonging the mixing operation has the mixing of fluids been effected. There are many instances, however, where intimate mixing must be accomplished within relatively short periods of time, such as in the mixing of volatile fuels, volatile liquids, gaseous constituents under a controlled pressure and temperature, and changeable-state materials which freeze, or harden, after a short period of time. Accordingly, the mixing operation must be completed within the shortest time possible to eliminate the risk of having the ingredients change chemically or change their states before the mixing has been effected.

It is an object of the invention to provide a stirrer for directing fluids or gases into passages therethrough upon rotation to produce maximum turbulence and, therefore, intimate mixing of the fluids or gases.

Another object is the provision of a stirrer having a shaft with a surrounding flange with passages and ports with axes oriented with respect to one another to achieve maximum turbulence of fluids or gases directed outwardly from the central shaft by centrifugal force.

A further object is to provide a stirrer designed to produce maximum turbulence of materials to be mixed within the shortest possible time of operation.

Still another object of the present invention is the provision of a stirrer designed to produce maximum turbulence and mixing with a minimum of structural elements.

A stirrer illustrating certain features of the invention may include a shaft having a circumferential flange pro vided with a plurality of passages and ports extending outwardly therethrough with axes on radii inclined from the shaft axis such that the inner ends of the ports open above the inner ends of the passages and the outer ends of the ports open below the outer ends of the passages in relation to the axis of the shaft when oriented vertically. Fluid in which the stirrer flange is submerged is directed by centrifugal force axially through the ports downwardly and through the passages upwardly whereupon thorough mixing of fluids or flowable solids is accomplished upon rotation of the shaft.

A complete understanding of the invention may be had from the following detailed description of a specific embodiment thereof when read in conjunction with the appended drawings, wherein:

FIG. 1 illustrates a plan view of the stirrer depicting the staggered relationship of the port and passage axes provided in the stirrer plate; and

FIG. 2 is a cross-sectional View taken along the line IIII of FIG. 1 and showing the flange of the stirrer mounted for rotation with a shaft.

Referring now to the drawings wherein like reference "ice characters designate like or corresponding parts throughout the several views, there is shown in FIG. 1, which illustrates a preferred embodiment, a member generally designated as numeral 11 which is annular in configuration and provided with opposed truncated conical hollow portions. A centrally-disposed shaft 12 is connected by suitable means such as a key 13 to a hub or web 14 of the member 11 with the vertical axis of the shaft being the axis of revolution of the conical portions. A circular flange 15 is integrally formed with the hub 14, and is of diamond configuration in cross-section as defined by a vertical cutting plane extending radially across the flange either to the right or to the left of the shaft 12 when viewed as shown in FIG. 2, therefore providing opposed parallel faces 16, 17, and 18, 19, respectively. The faces 17 and 18 are conical in form about the shaft axis and the hub 14- spaces the faces from the shaft 12 for a purpose to be explained more fully hereinafter. The diamond radial cross-sectional configuration is only one example of the shape in which the flange 15 may be formed. For instance, the radial cross-section of the flange 15 may be oval or round, the principal consideration being the orientation of the axes of the apertures through the disc 11 as will become more evident in the following description.

The annular flange 15 is designed such that a horizontal plane passed through the center point of the hub or web 14 normal to the axis of the shaft 12 includes diametrically-opposed points of the cross-sectional diamond shape of the flange 15 when taken radially from the shaft axis and also including the center of the diamond shape. Further, a line parallel to the axis of the shaft 12 through the uppermost point of the diamond shape would extend through the center of the diamond shape and also through the lowermost point of the cross-sectional configuration of one half of the flange 15.

As best shown in FIG. 1, the member 11 is provided with a plurality of passages 21 which extend from the outer face 16 of the flange 15, through the flange, to open on the face 17. The axes of the passages 21 extend upwardly from the shaft 12 and preferably make angles of 45 measured clockwise with the axis of the shaft 12, as shown in FIG. 2. The passages have inner ends opening on the shaft 12 at face 17 which are spaced by arcs of equal magnitude. The outer ends of the passages open on the face 16 at an elevation above that of their inner ends, and are spaced equally on the face 16.

Ports 22 extend through the flange 15 from face 18 to face 19, and the axes of these ports are inclined radially from the shaft 12 outwardly and downwardly with the axes of the passages 21 and the axes of the ports 22 being in opposition, for example. The ports 22 have inner ends opening on the shaft 12 and spaced by arcs of equal magnitude through the surface or face 18 and alternate with the apertures 21 in their positions about the axis of the shaft 15.

It has been found desirable to have the axes of both the passages 21 and ports 22 off-center with respect to the diamond-shape flange cross-sectional configuration taken radially, as illustrated best in FIG. 2. The center of gravity of the flange 15 therefore lies as close as possible to the axis of the shaft 12, stabilizing the assembled flange and shaft especially during a mixing operation. The passages 21 have their axes displaced outwardly from a plane including the loci of mid-points between parallel faces 18 and 19, and the ports 22 have their axes displaced outwardly from a plane including the loci of mid-points between parallel faces 16 and 17. The stirrer hub or web 14 is strengthened by the design of the off-center apertures as may be appreciated by referral to FIG. 2. The thick portions 23 and 24 are formed integrally with the hub 14, and the hub is of suitable thickness to withstand torsional stress and strain encountered during the mixing of dense fluids.

A salient feature of the suggested placement of the axes of the passages 21 and ports 22 at ninety degrees with respect to one another is the achievement of a flow pattern which leads fluid downwardly and outwardly through openings 22 and upwardly and outwardly through apertures 21 by centrifugal force. The flow path is indicated by arrows in FIG. 2 as applied to the diamond-shaped flange configuration taken at one side of the shaft 12. In this manner a figure eight flow stream is effected in the agitated fluid with the cross of the eight occurring by stream flow through the flange in opposite directions in passages 21 and ports 22, regardless of the direction of rotation of the disc 11.

Having described in detail the structural features of the stirrer, the operation may be readily understood. The stirrer is inserted into a container having liquids or flowable material to be mixed intimately. The stirrer shaft 12 is rotatively driven and liquid is forced upwardiy through passages 21 and downwardly through ports 22 in directions 90 opposed. The liquid streaming from the outer ends of the passages and ports in the paths depicted by the arrows creates turbulence in the liquids which assures commingling and the maximum mixing of the ingredients.

The design of the stirrer as hereinbefore described is such that the paddles or blades of a beater or stirrer are wholly eliminated. Accordingly, the hazards of revolving blades are obviated, and it is possible to touch the improved stirrer flange tangentially as it revolves without harm to container walls, thermometers, and other instruments associated with a mixing operation.

It is manifest that the above-described embodiment of the invention is merely illustrative and that numerous modifications may be made within the spirit and scope ones extending through the flange upwardly and outwardly from the concavity in the bottom and terminating outwardly from the concavity in the top whereby an X flow pattern is established with the flow stream downwardly and outwardly through the ports and upwardly and outwardly through the passages.

.2. A stirrer comprising a rotary shaft, a hub fixed on the shaft, and a circumferential flange fixed to the hub with passages and ports formed therethrough on axes inclined with respect to the shaft axis and radial thereto, the passage and port axes being at 'an angle with respect to one another such that the inner ends of the passages open on the shaft at a level lower than the inner ends of the ports and a .liquid containing the flange is caused by centrifugal force to flow outwardly and upwardly through the passages and outwardly and downwardly through the ports upon rotation of the shaft.

3. A stirrer comprising a vertical shaft, a hub connected to the shaft, and a circumferential flange fixed to the hub having opposed conical hollow portions truncated by the .hub with the shaft axis being the axis of revolution of the conical hollow portions, the hub spacing the walls of the hollow conical portions radially from the shaft, the flange being formed with passages and ports on radii inclined from the axis of the shaft, the axes of the ports extending downwardly and outwardly and the axes of the passages extending upwardly and outwardly whereby a liquid within which the flange is submerged is caused to flow in the described direction of the axes, the flange ports and passages being in alternate arrangement about the axis of the shaft.

4. A stirrer as in claim 3 wherein the flange radial cross-section is diamond shaped.

5. A stirrer comprising a vertical shaft, a hub fixed to the shaft, and a flange connected to the hub and surrounding the shaft and radially spaced therefrom by the hub, the flange having a plurality of radially extending ports therethrough on axes inclined downwardly from the axis of the shaft and opening at their inner ends adjacent the shaft and at their outer ends remote from the shaft and at a lower level than the elevation of the inner ends, the flange also having a plurality of radially extending passages therethrough on axes inclined upwardly from the axis of the shaft and opening at their inner ends adjacent the shaft and below the level of the inner ends of the ports, the flange passages having outer ends opening at a level above the openings of the outer ends of the ports and above the level of the inner ends of the passages wherebyrotation of the flange when submerged in a liquid causes by centrifugal force Liquid to flow upwardly and outwardly through the flange passages and downwardly and outwardly through the flange ports, and the flange being thickened adjacent the shaft for locating the mass of the stirrer approximate the shaft axis for stabilization thereof when rotated.

6. A stirrer as in claim 5 wherein the midpoints of the axes of the passages and ports lie in a common circle center on the axis of the shaft.

7. A stirrer as in claim 6 wherein the passages and ports are arranged alternately about the axis of the shaft.

8. A stirrer comprising a vertical shaft, a hub connected to the shaft and a circumferential flange fixed to the hub, the flange being formed with passages and ports on radii inclined from the axis of the shaft, the axes of the ports extending downwardly and outwardly and the axes of the passages extending upwardly and outwardly whereby a liquid within which the flange is submerged is caused to flow in the described direction. of the axes, the flange ports and passages being in alternate arrangement about the axis of the shaft, the flange radial cross-section being oval shaped.

49. A stirrer comprising a vertical shaft, a hub connected to the shaft and a circumferential flange fixed to the hub, the flange being formed with passages and ports on radii inclined from the axis of the shaft, the axes of the ports extending downwardly and outwardly and the axes of the passages extending upwardly and outwardly whereby a liquid within which the flange is submerged is caused to flow in the described direct-ion of the axes, the flange ports and passages being in alternate arrangement about the axis of the shaft, the flange radial cross-section being round.

References Cited in the file of this patent UNITED STATES PATENTS 2,106,529 Keller Jan. 25, 1938 2,485,216 Seburger Oct. 18, 1949 FOREIGN PATENTS 749,327 Great Britain May 23, 1956 

2. A STIRRER COMPRISING A ROTARY SHAFT, A HUB FIXED ON THE SHAFT, AND A CIRCUMFERENTIAL FLANGE FIXED TO THE HUB WITH PASSAGES AND PORTS FORMED THERETHROUGH ON AXES INCLINED WITH RESPECT TO THE SHAFT AXIS AND RADIAL THERETO, THE PASSAGE AND PORT AXES BEING AT AN ANGLE WITH RESPECT TO ONE ANOTHER SUCH THAT THE INNER ENDS OF THE PASSAGES 